1. Field of the Invention
The present invention relates to a lens device and to lens drive in an image capturing device including a lens device.
2. Description of the Related Art
There are a television camera and a digital camera capable of automatically adjusting the zoom or focus without being manually operated by a user. In such cameras, if electric power is always supplied to a circuit related to the zoom and focus adjustment (even when zoom and focus driving are not performed), electric power is uselessly consumed. Thus, it is proposed to stop supplying electric power under a predetermined circumstance to reduce power consumption. Japanese Patent Application Laid-Open No. 2005-156738, for example, describes a television camera system performing autofocus (hereinafter referred to as AF), in which power consumption is reduced by stopping electric power supply to a part of or all of circuits in consideration of a length of time required from turning on the power until starting each of the circuits in AF mode.
Specifically, in Japanese Patent Application Laid-Open No. 2005-156738, the system is configured to stop electric power supply to a part of or all of the circuits constituting AF means when AF control is stopped, and start electric power supply to all of the circuits when the AF control is started.